Magnetic Engines Could Help Satellites Stay in Orbit Longer

Why use ball bearings when you could use magnets?

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By
David Grossman

Researchers have developed a new method for getting satellites to orbit the Earth and it involves magnetic levitation.

Current satellites often rely on a type of flywheel called a reaction wheel. These wheels let satellites store angular momentum by spinning at a constant speed, and then use it by stopping the wheel suddenly, which translates into orbit adjustments. A failed reaction wheel has been the cause of more than one malfunction, the Hubble Telescope has had to be serviced twice to repair malfunctioning wheels. Similarly, when two out of four of the Kepler telescope's reaction wheels failed in 2013, it was widely feared that it would become space junk.

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Reactions wheels rely on ball bearings, which take up space, require attention and lubrication, and have not proven to be 100 percent precise. The researchers at Celeroton, a company specializing in high speed motors, have used magnets to create a "floating motor" that does not wear out.

The Celeroton motor

There are several potential advantages to this system. First of all, it's faster. A Celeroton motor spins at 150,000 RPMs per second, compared to 6,000 with ball bearings. It's also less sensitive. Magnetic support, says Arda Tüysüz—a Celeroton researcher who was an author of the paper presenting the findings—"also allows us to avoid the vibrations" that can cause ball bearings to become unhinged. As the Celeroton paper notes, by using magnetic bearings instead of ball bearings, "a smooth torque can be achieved also at speed zero crossings."

The motor is currently a prototype, and the focus is on smaller satellites, weighing up to a few hundred pounds at the max. But still, Engadget is reporting that multiple space-faring agencies and companies, including the European Space Agency, are giving the new engine a hard look. Maybe they should also give greaseless bearings a try.